Fuel supply installation for injection-type internal combustion engines



Jan. 13, 1970 H. DINGER 3,489,128

FUEL SUPPLY INSTALLATION FOR INJECTION-TYPE INTERNA OMBUSTION ENGINES Fil July 14, 1967 INVENTOR HANS DINGER ATTORNEYS Unitcd States Patent 3,489,128 FUEL SUPPLY INSTALLATION FOR INJECTION- TYPE INTERNAL COMBUSTION ENGINES Hans Dinger, Stuttgart, Germany, assignor to Daimler- Beuz Aktiengesellschaft, Stuttgart Unterturkheim, Germany Filed July 14, 1967, Ser. No. 653,381 Claims priority, applicatiog 6Goermany, July 16, 1966,

2 Int. Cl. F02m 59/00 US. Cl. 123136 12 Claims ABSTRACT OF THE DISCLOSURE A fuel supply installation for an injection-type internal combustion engine in which the fuel tank is connected with the fuel injection unit by way of a fuel supply line including a fuel filter, and in which the suction space of the injection unit is connected by way of an overflow valve with the fuel return line leading back to the tank, whereby a fuel pump supplies fuel from the fuel tank to the injection unit by way of the fuel supply line; the leakage-fuel collecting line which is connected with the injection valves for the working cylinders, in turn, is operatively connected with the fuel return line by way of a connecting piece which includes an injector pump so that the fuel flowing back from the suction space of the injection pump into the tank creates a suction effect taking along the fuel in the leakage-fuel collecting line. The connecting piece itself may be formed as an integral part of the housing of the fuel filter whereby the connection for the fuel return line at the outlet side of the filter is connected with the filter space by way of a venting line.

BACKGROUND OF THE INVENTION The present invention relates to a fuel supply installation for injection-type internal combustion engines provided with a fuel supply line between fuel tank and injection unit as well as with a fuel return line connected to the suction space of the injection pump and leading back to the fuel tank, a connecting piece for a common 1eakage-fuel collecting line which is arranged in the fuelreturn line being communication or connection with the injection valves of the working cylinders.

Such types of fuel supply installations may be equipped in an advantageous manner with only one separable connection each for the fuel supply and the fuel return between the fuel tank and the internal combustion engine and are particularly suitable therefore for the installation into driving engines for vehicles in which the assembly and disassembly of the drive unit is necessary relatively frequently.

SUMMARY OF THE INVENTION The aim underlying the present invention essentially resides in improving the fuel supply installation of the aforementioned type.

For this purpose, provision is made accordingto the present invention that the connecting piece is provided with a pumpespecially with a jet or injector pump arranged in the fuel-return line, to the suction space of which is connected the common leakage-fuel collecting line.

Significant advantages are achieved by the present invention. Fuel can no longer escape at the leakage places from the leakage-fuel collecting line in case of occurring leaks as the vacuum in the suction space of the pump counteracts this escape. The leakage-fuel lines are located in part in the cylinder head unshielded with respect to the oil spaces.

3,489,128 Patented Jan. 13, 1970 It is avoided by the present invention that the lubricating oil is thinned by escaping fuel. The present invention gains in significance in particular with multi-cylinder internal combustion engines in which, by reason of the large number of Working cylinders, the leakage-fuel collecting lines are particularly prone to troubles as regards occurrence of leakages by reason of the large length of the lines, of the relative slight diameter of the lines, and of a large number of connecting places.

It is known in connection with fuel supply installations of the aforementioned type that a fuel filter is arranged in the fuel supply line which is in communication or is operatively connected with the fuel return line by a vent line by way of the connecting piece. In the application of the present invention to such types of fuel supply installations, the housing of the fuel filter may be constructed, in a structural simplification, in one piece, i.e., unitary with the connecting piece.

The housing of the fuel filter may be provided according to a further development of the present invention with a housing connection at the inlet and outlet side for the return line whereby these housing connections are operatively connected with each other by way of an injector nozzle.

According to a further advantageous construction of the present invention, a housing channel of the fuel filter forming the venting line may terminate in the housing connection thereof at the outlet side for the fuel return line.

Accordingly, it is an object of the present invention to provide a fuel supply installation for internal combustion engines which avoids by simple means the aforementioned shortcomings and drawbacks encountered with the prior art constructions.

It is another object of the present invention to provide a fuel supply installation of the aforementioned type which improves its performance and reliability in operation.

A further object of the present invention resides in a fuel supply installation for injection-type internal combustion engines which minimizes the danger of leakage of fuel in the leakage-fuel collecting line.

Still a further object of the present invention resides in a fuel supply installation of the type described above which permits the location of the leakage fuel lines within the cylinder head without requiring shielding thereof with respect to the oil spaces.

Still another object of the present invention resides in a fuel supply installation for injection-type internal combustion engines in which the danger of thinning of the lubricating oil by leaking fuel is practically eliminated.

Another object of the present invention resides in a fuel supply installation which can be readily installed and disassembled for purposes of servicing and which excels by a considerably lesser likelihood of the occurrence of leakages notwithstanding the physical construction and lay-out of the installation.

A further object of the present invention resides in a fuel supply installation for injection-type internal combustion engines of the type described above which permits a structural simplification of the housing for the fuel filter.

These and further objects, features, and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

FIGURE 1 is a schematic view of a fuel supply installation in accordance with the present invention;

FIGURE 2 is an axial cross-sectional view, on an enlarged scale, through the fuel filter of FIGURE 1; and

FIGURE 3 is a partial cross-sectional view (on a still further enlarged scale) through the connecting piece at the housing of the fuel filter provided with an injector pump in accordance with the present invention.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, reference numeral designates in FIG- URE 1 an injection-type internal combustion engine serving for the drive of a vehicle while reference numeral 11 designates a fuel tank secured at the vehicle frame or any suitable part of the vehicle in a conventional manner (not illustrated). Only one fuel supply line generally designated by reference numeral 12 and one fuel return line generally designated by reference numeral 13 is provided between the internal combustion engine 10 and the tank 11. Both fuel lines 12 and 13 are provided with a separable connection 12c and 13b, respectively for the installation and disassembly of the injection-type internal combustion engine 10.

A fuel pump 15 of conventional construction which is arranged in the section 12a at the engine side of the fuel supply line 12 supplies the fuel through a fuel filter generally designated by reference numeral 16 to the injection pump 25 of conventional construction of the internal combustion engine 10. Injection lines 17-24 lead from the injection pump 25 to the injection valves (not shown) for the combustion spaces of the eight working cylinders of the injection-type internal combustion engine 10. Each of the injection valves is connected with a common leakage-fuel collecting line generally designated by reference numeral 26. The connecting places 27-30 in the leakage-fuel collecting line 26 for the four injection valves of one of the two cylinder rows mutually arranged in V-shape of the internal combustion engine 10 are visible in the drawing.

The injection pump 25 is provided with a conventional fuel overflow valve 31 in communication with its suction space to which is connected the section 13a of the fuel return line 13 at the engine side.

The section of the fuel supply line 12 connecting the fuel filter 16 with the injection pump 25 is designated in FIGURE 1 by reference numeral 12b.

The fuel filter 16 is provided for purposes of connection with the fuel supply line 12 with a housing connection 32 and 33 at the inlet and outlet side thereof, respectively.

As is shown in particular in FIGURES 2 and 3, the housing 34 of the fuel filter 16 is provided with a fixed connecting piece 34a for the fuel return line 13 and the leakage-fuel collecting line 26. The connecting piece 34a is equipped on the one hand, with a housing connection 35 at the inlet side as Well as with a housing connection 36 at the outlet side for the fuel return line 13 and, on the other with a further housing connection 37 at the inlet side for the leakage-fuel collecting line 26.

A housing channel 38 which is in communication with a venting bore 39 within the housing cover 40 of the fuel filter 16, terminates in the housing connection 36 at the outlet side for the fuel return line 13.

The housing connections 35 and 36 for the fuel return line 13 in the connecting piece 34a are connected with each other by a jet or injector pump generally designated by reference numeral 41 (FIG. 3). The miixng chamber 42 of the injector pump 41 is constituted by a housing bore 43 within the connecting piece 34a, into which projects an injector nozzle 44. The mixing chamber 42 is in communication, on the one hand, by way of the injector nozzle 44 with the housing connection 35 at the inlet side as well as by way of a connecting channel 45 arranged coaxially to the injector nozzle 44 with the housing connection 36 at the outlet side for the fuel return line 13. On the other hand, a connecting channel indicated in dash line by reference numeral 46 which is disposed perpendicularly to the axis of the injector nozzle 44, terminates in the mixing chamber 42 and leads to the housing connection 37 at the inlet side for the leakage-fuel collecting line 13.

OPERATION The operation of the described fuel supply installation is as follows:

With a running injection-type internal combustion engine 10 the fuel is supplied by the pump 15 from the tank 11 by way of'the fuel filter 16 to the injection pump 25. The fuel reaches the injection valves from the injection pump 25 through the injection lines 17-24. The excess fuel in the suction space of the injection pump 25 flows by way of the overflow valve 31 and the return line section 13a to the housing connection 35 of the connecting piece 34a at the fuel filter 16.

The leakage fuel from the injection valves reaches the mixing chamber 42 by way of the connections (27-30) of the leakage-fuel collecting line 26 and the housing connection 37 in the connecting piece 341:. The leakage fuel is thereby taken along by the fuel flowing back into the fuel tank 11 by way of the injector nozzle 44 into the section of the return line 13 connected at 36.

Due to the sub-atmospheric pressure prevailing within the mixing chamber 42, no fuel can escape from those places where leakage might otherwise occur in the leakage-fuel collecting line 26.

With specially constructed fuel supply circulation systems, the overflow valve 31 can be omitted. The fuel pressure in the suction space of the injection pump 25 is then determined by the throttling effect of the injector pump 41. A higher pressure drop thereby occurs at the latter and the suction effect is further improved as regards line 26.

While I have shown and described one embodiment, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a persons skilled in the art, and I therefore do not wish to be limited to the details shown and described herein.

I claim:

1. A fuel supply installation for injection-type internal combustion engines having a fuel supply line between a fuel tank and an injection unit as well as a fuel return line connected to the suction space of the injection pump and leading back to the fuel tank, and a connecting means provided in the fuel return line for a leakage-fuel collecting line operatively connected with the injection valves of the working cylinders, wherein the improvement comprises pump means providing a sub-atmospheric pressure in the leakage-fuel collecting line for preventing escape of leakage fuel therefrom which would dilute the lubricating oil, said pump means being arranged in the fuel return line and having a suction space, the leakage-fuel collecting line being operatively connected with the suction space of said pump means, wherein said pump means is arranged 'within said connecting-means and is an injector-type pump having a nozzle conducting the fuel from the injection pump therethrough as the motive fluid, said suction space surrounding said nozzle and being in fluid communication with said collecting line.

2. A fuel supply line according to claim 1 wherein said connecting means is in the form of a connecting piece.

3. A fuel supply line according to claim 2, further comprising fuel filter means in the fuel supply line, venting line means operatively connecting said filter means with the fuel return line by way of the connecting piece of said connecting means, said filter means having a housing constructed in one piece with said connectiong means.

4. A fuel supply installation according to claim 3, wherein the housing of the filter means is provided with housing connection means for the fuel return line at the inlet and outlet side, said housing connection means being operatively connected with each other by way of an injector nozzle.

5. A fuel supply installation according to claim 4, wherein a housing channel of the fuel filter means forms said venting line means, said housing channel terminating in the housing connection means for the fuel return line at the outlet side.

6. A fuel supply installation for injection-type internal combustion engines having a fuel supply line between a fuel tank and an injection unit as well as a fuel return line connected to the suction space of the injection pump and leading back to the fuel tank, and a connecting means provided in the fuel return line for a leakage-fuel collecting line operatively connected with the injection valves of the working cylinders, wherein the improvement comprises pump means arranged within said connecting means and providing a sub-atmospheric pressure in the leakage-fuel collecting line for preventing escape of leakage-fuel therefrom which would dilute the lubricating oil, said pump means being arranged in the fuel return line and having a suction space, the leakage-fuel collecting line being operatively connected with said suctionspace of said pump means, further comprising fuel filter means in the fuel supply line, venting line means operatively connecting said filter means with the fuel return line by way of said connecting means, said filter means having a housing constructed in one piece with said connecting means.

7. A fuel supply installation according to claim 6, wherein the housing of the filter means is provided with housing connection means for the fuel return line at the inlet and outlet side, said housing connection means being operatively connected with each other by way of an injector nozzle.

8. A fuel supply installation according to claim 7,

6 wherein a housing channel of the fuel filter means forms said venting line means, said housing channel terminating in the housing connection means for the fuel return line at the outlet side.

9. A fuel supply installation according to claim 6, wherein a housing channel of the fuel filter means forms said venting line means, said housing channel terminating in the housing connection means for the fuel return line at the outlet side.

10. A fuel supply installation according to claim 6, wherein said pump means is arranged in said connecting means.

11. A fuel supply line according to claim 10, wherein said connecting means is in the form of a connecting piece.

12. A fuel supply line according to claim 7, wherein said pump means is an injector-type pump.

References Cited UNITED STATES PATENTS 1,304,550 5/1919 Edison 123-436 2,878,889 3/1959 Gilbert 123-136 XR 2,928,499 3/1960 Nallinger 210-168 XR OTHER REFERENCES Fuel Injection and Controls for I.C.E. by P. G. Burman and F, Deluca (1962), TJ787B8C2, copy gr. 340, (p. 244).

LAURENCE M. GOODRIDGE, Primary Examiner US. Cl. X.R. 3-1 9 

